Earlier marine biologists assumed that fish did not have the brain power to co-operate with other fish, but now, according to a new research some fish pairings look out for each other while searching for food.

SMH wrote that scientists have found some species of birds and mammals helping out one another, but they used to think that such a behavior needed a highly developed brain and social skills, which is sadly not possessed by fish.

But, ARC Centre of Excellence for Coral Reef Studies has observed rabbitfish in Queensland guarding each other as their mate searched for food. According to researcher Dr Simon Brandl, the fish were strict regarding co-ordinating their watchful behavior.

The researchers noticed that when a fish was in a still, upright position, their mate felt much comfortable to feed.

The researchers compared the behavior of these fish to the ones hunting for food alone, and discovered that fish, going to hunt in pairs take more 'consecutive bites and penetrate deeper into crevices', and suggested said this method was a benefit.

Dr Brandl said that such a behavior is so far unique in fishes and seemed to be based on reciprocal co-operation between pair members.

A number of researchers have been debating since long on whether animals can cooperate without having highly developed cognitive and social skills, like those found in humans, primates and a few species of bird life. The research has come up as a surprise for them.

Dr Brandl said, "By showing that fishes, which are commonly considered to be cold, unsocial, and unintelligent, are capable of negotiating reciprocal co-operative systems, we provide evidence that co-operation may not be as exclusive as previously assumed".

"This may also require a shift in how we study and ethically treat fishes," Professor Bellwood said.

"This behaviour is so far unique among fishes and appears to be based on reciprocal co-operation between pair members," Dr Brandl said.

"By showing that fishes, which are commonly considered to be cold, unsocial, and unintelligent, are capable of negotiating reciprocal co-operative systems, we provide evidence that co-operation may not be as exclusive as previously assumed," Dr Brandl said.

"This may also require a shift in how we study and ethically treat fishes," Professor Bellwood said.